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framebuffer_driver.c
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framebuffer_driver.c
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#include "io.h"
/* The I/O ports */
#define FB_COMMAND_PORT 0x3D4
#define FB_DATA_PORT 0x3D5
/* The I/O port commands */
#define FB_HIGH_BYTE_COMMAND 14
#define FB_LOW_BYTE_COMMAND 15
#define FB_BLACK 0
#define FB_WHITE 15
unsigned short fb_cursor_pos = 0x00000000;
char *fb = (char *) 0x000B8000;
/** fb_write_cell:
* Writes a char with the given foreground and background to position i
* in the framebuffer.
*
* @param i The location in the framebuffer
* @param key The character
* @param fg The foreground color
* @param bg The background color
*/
void fb_write_cell(unsigned int i, char key, unsigned char fg, unsigned char bg)
{
fb[i * 2] = key;
fb[i * 2 + 1] = ((fg & 0x0F) << 4) | (bg & 0x0F);
}
/** fb_move_cursor:
* Moves the cursor of the framebuffer to the given position
*
* @param pos The new position of the cursor
*/
void fb_move_cursor(unsigned short pos)
{
outb(FB_COMMAND_PORT, FB_HIGH_BYTE_COMMAND);
outb(FB_DATA_PORT, ((pos >> 8) & 0x00FF));
outb(FB_COMMAND_PORT, FB_LOW_BYTE_COMMAND);
outb(FB_DATA_PORT, pos & 0x00FF);
fb_cursor_pos = pos;
}
void fb_write(char *buf, unsigned int len)
{
unsigned int i;
for(i=0;i<len;i++){
fb_write_cell(fb_cursor_pos, buf[i], FB_BLACK, FB_WHITE);
fb_move_cursor(fb_cursor_pos + 1);
}
}